How to send push notifications to specific users firebase

Question

I'm trying to send out a push notification from a teacher to a student, for example. I'm using firebase and I've already got that token from each device and saved it on firebase to the wanted user, and setup my FirebaseMessagingService. Now I want to be able to send a notification, programmatically, whenever a teacher clicks on a student in a list, for example. How do I do that? I've been looking for a solution for a couple of days and couldn't find an answer. Thanks :)

Answer 1

This is what I did. And it works. I know, because I was up all night trying to get this thing to work.

admin.messaging().sendToDevice(token, msg)
.then(resMsg => {
   console.log("Successfully sent message", resMsg);
}).catch(err => {
   console.log("Error sending message", err);
})

Where token is the FCM token from the client device. And the msg is a JSON payload of the following structure:

const msg ={ 
             notification: {
               title: 'It\'s the last day of the week!',
               body: `It's Sunday! Don't forget to refresh Dashboard with your latest activity data!`,
             }, 
           };

Source Build a transactional push notifications system using only Firebase

Answer 2

For sending push notifications with firebase you need to use the FCM API which can be found here: https://firebase.google.com/docs/cloud-messaging/server .
Assuming you use Java for your software you could take a look at this quickstart example provided by google: https://github.com/firebase/quickstart-java/blob/master/messaging/src/main/java/com/google/firebase/quickstart/Messaging.java or look for a complete library.

You just need to add some logic to your application that triggers the FCM API with the correct token and payload.